Was Christopher Columbus on a religious crusade?

Two recent books argue that explorers Christopher Columbus and Vasco da Gama were more like Christian crusaders than greedy mercenaries or curious adventurers. Other historians, however, remain skeptical.

The books, released in the weeks leading up to Columbus Day (Oct. 10), claim the reason the famous navigators sought a direct trade route to India was to undermine Islam.

“I think historians have known about this, but they haven’t taken it seriously,” said Carol Delaney, author of “Columbus and the Quest for Jerusalem.” Delaney, a retired anthropologist, is currently a research scholar at Brown University.

Delaney’s book argues that Columbus wanted to find gold to finance a new crusade to recapture Jerusalem from the Muslims, believing that Jerusalem must be in Christian hands before Jesus’ Second Coming....